Could a nuclear explosion deactivate an erupting volcano?
No, because volcanoes are not turned on and off like a switch. This may have made a storyline in a B-movie in the 50s and 60s, but in real life things are different. A volcano erupts because pressure has built up in a chamber located underground – the magma chamber. The eruption is the mechanism by with the pressure in the chamber is relieved. Plugging the vent through which the magma is rising will not remove the pressure. Underground nuclear tests usually produce one of two results. If the nuclear device is fairly close to the surface, the explosion creates a large cavity which then collapses because the roof is inadequately supported. This creates a crater at the explosion site. If the explosion is deeper, it produces a (roughly) spherical cavity. Much of the rock and earth in the immediate vicinity of the explosion is vapourized or, as the distance from the centre of the blast increases, is melted. This material collects at the bottom of the cavity where it gradually solidifies. Th
